McLaren has struggled for pace this year, but Magnussen has still impressed, scoring a podium on his debut ahead of his team-mate. Button has scored 14 points more than Magnussen but the pair are tied 4-4 in qualifying and Dennis believes Button needs to up his game.

"I'm happy with the drivers in the sense that I think they are giving their best," Dennis told Sky Sports. "I'm sure Kevin is giving a big wake-up call for Jenson, and in some ways you say, 'Great, we've made a great choice with Kevin' but in other ways you say, 'Come on Jenson, you are a world champion and one thing you can do on a consistent basis - and you should be doing it - is beating your team-mate'.

"Do I want him to try harder? Of course I do - he's a highly-paid grand prix driver. Yes, we are not giving him the best car and, yes, it would challenging for him to win in it, to say the least, but he could do his bit and Kevin has to make it as difficult for him as possible."

Rumours are already circulating that McLaren is hoping to sign big-name driver for next year, with Fernando Alonso and even Lewis Hamilton linked to the team. Dennis is keeping his options open, but said neither of McLaren's current drivers should feel threatened.

"We want to win races and we would always hope that the best available drivers would wish to drive our cars. The key word is 'available' because people have contracts and we respect those contracts, but if Lewis was in a position to drive for us next year, as with many of the other top drivers if they were in that position, we'd love to have them on board. No one should ever feel threatened, either drivers or engineers, all we want to do is win and we have to take considered positions and considered decisions on that process."